So if one gets food poisoning like salmonella or e.coli, it doesn't go thru into the breast milk?
Correct.
Taken from Breastfeeding Answer Book, Third Revised Edition (2003) page 537
If a mother has food poisoning breastfeeding can continue.
When a mother eats a food that is contaminated with specific bacteria or toxins, she may develop “food poisoning” which can cause vomiting, abdominal cramps and diarrhoea. Food poisoning may be caused by botulism, listeriosis, salmonella, shigella, cigutera, e. coli or other bacteria.
In the vast majority of cases, food poisoning remits within a few days causing no further problems. It poses no danger to the breastfeeding baby, although the breastfeeding mother with diarrhoea and vomiting should be encouraged to drink enough liquids to maintain her fluid balance and avoid dehydration.
Some mothers may contract such a serve case of food poisoning that antibiotics are needed, most of which are considered compatible with breastfeeding. Depending upon which bacteria are involved, other precautions may be recommended to prevent airborne or direct-contact transition between mother and baby, such as careful hand-washing and wearing a mask while breastfeeding (Lawrence and Lawrence, pp 564-66)
I also read a research report about introducing the salmonella bacteria to newborn calves. It took the cows around two hours to start producing the antibodies to salmonella in their milk. (I’m sure you can understand why we can’t repeat this experiment with human newborns.)
Best wishes,
SARAH